JPH05277658A - Method for controlling molten metal surface level in twin roll type continuous casting - Google Patents

Abstract

PURPOSE:To provide a control method for molten metal surface level, by which the level of a molten metal pouring basin part in twin roll type continuous casting for producing a cast strip is precisely controlled by using a CCD camera. CONSTITUTION:In this control method for molten metal surface level, on contact limiting plates 4 inserted into the molten metal pouring basin part 3 formed between two rolls 1 and fixing the solidified start point of the molten metal, refractory coating having different gray degree with the poured molten metal is applied and the picture of the contact limiting plate 4 is taken by an optical type molten metal surface recording camera 11, and the molten metal surface 10 in the pouring basin part 3 is recognized to control the molten metal surface level based on the recognized value. By this method, the recognizing ability of the CCD camera for controlling the molten metal surface level is improved and the molten metal surface control is facilitated and the cast strip securing the stable operation and having excellent surface characteristic is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls the level of a pool in an twin roll type continuous casting for producing a thin plate slab using an optical surface recording camera (hereinafter referred to as a CCD camera). The present invention relates to a molten metal level control method.

[0002]

2. Description of the Related Art A twin-roll type continuous casting method in which molten steel is poured between two rolls rotating inward and a thin metal plate is cast is known as a Bessemer method.

In Japanese Laid-Open Patent Publication No. 3-99757, for example, as shown in FIG. 3, side dams 2 are attached to opposite side surfaces of an upper part of a roll 1 to form a pool 3 of molten metal with the roll. . A contact limiting plate 4 is installed on each of the roll surfaces of the basin 3.

The molten metal injected from the injection nozzle 5 into the basin 3 is cooled from the solidification start point 6 in contact with the roll 1 to start solidification, and is formed on both roll surfaces at the roll kiss point 7. The solidified shell 8 is integrated and pulled out downward to form a cast piece 9.

During the casting process, the amount of molten metal injected from the injection nozzle 5 changes, and the molten metal surface 10 of the molten metal pool 3 changes due to the rotation of the drum, which causes the solidified shell 8 to be formed. Cooling rate, thickness, etc. of the
This causes fluctuations in the thickness of the slab 9 and deterioration of the surface quality, which makes stable operation impossible. Therefore, the surface 1 of the pool 3
Control of 0 must be strictly controlled in terms of stable operation and quality maintenance.

[0006]

By the way, as a means for controlling the molten metal surface, an optical molten metal surface camera has been conventionally used. This camera is widely used because it can remotely control the surface of the basin and controls the surface of the basin, which makes it extremely suitable for shooting at high temperatures and in a narrow space.

However, when observing the surface of the basin with an optical surface camera, the brightness of the contact limiting plate 4 and the surface 10 is very high, and it is difficult to identify them on the camera screen. It was difficult to observe the bath surface 10.

The present invention has been made in view of the above problems.
(EN) Provided is a level control method for a molten metal, which enables easy identification of a contact limiting plate and accurately observes the molten metal surface using a CCD camera.

[0009]

According to the present invention, in the twin roll type continuous casting in which a contact limiting plate for fixing the solidification start point of the molten metal is charged in a pool portion formed between two rolls, the contact is made. Applying a refractory paint with a gray degree different from that of the molten metal to be poured into the limiting plate, and optical surface recording camera (CCD camera)
A method for controlling a molten metal level in twin-roll continuous casting, characterized in that the molten metal level of the molten metal pool is recognized by photographing the contact limiting plate, and the molten metal level is controlled based on the recognized value.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings with reference to the drawings.

FIG. 1 is a view for explaining a state in which the molten metal surface 10 is imaged by a CCD camera 11 in twin roll type continuous casting. The contact limiting plate 4 has a refractory paint having a gray degree different from that of the molten metal, for example, nitriding. Apply boron (BN) or the like.

The BN has a black color and the contact limiting plate 4
When this is applied, the wettability is lowered, so that molten metal, slag, and the like are less likely to adhere, and therefore the boundary between the contact limiting plate 4 and the molten metal surface 10 is clearly recognized.

FIG. 2 is a diagram showing an image projected on the screen of the CCD camera 11 when the contact limiting plate 4 is photographed. 4a shows an image of the contact limiting plate 4 in black and 10a shows hot water. The image on the surface 10 appears white, and the boundary line 12 between the two is clearly recognized.

Here, if the boundary line 12 moves to the left side of the figure, it means that the molten metal surface 10 has risen, and if it moves to the right side, it means that it has descended, so that this boundary line 12 is always in a fixed position. By controlling the amount of molten metal injected from the injection nozzle, stable operation is ensured and the quality of the slab is maintained.

[0015]

As described above, according to the present invention, the wettability of the contact limiting plate is lowered by applying a refractory paint having a gray degree different from that of the molten metal to the contact limiting plate for fixing the solidification start point of the molten metal. It is possible to prevent the adhesion of molten metal and inclusions and to enhance the recognition ability of the CCD camera for controlling the molten metal surface level, thus facilitating the molten metal surface control and ensuring stable operation. The quality of is maintained.

[Brief description of drawings]

FIG. 1 is a drawing for explaining a state of photographing a molten metal surface in a twin roll type continuous casting by a CCD camera.

FIG. 2 is a view showing an image of a contact limiting plate projected on a screen of a CCD camera.

FIG. 3 is a side view showing a twin-roll type thin plate continuous casting method.

[Explanation of symbols]

 1 Casting roll 2 Side weir 3 Hot water reservoir 4 Contact limiting plate 5 Injection nozzle 6 Solidification start point 7 Roll kiss point 8 Solidification shell 9 Cast slab 10 Hot water surface 11 CCD camera 12 Boundary line

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Morohoshi 20-1 Shintomi, Futtsu City, Chiba Shin Nippon Steel Co., Ltd.

Claims (1)

[Claims] 1. In twin roll type continuous casting in which a contact limiting plate for fixing the solidification start point of the molten metal is charged into a pool of water formed between two rolls, the molten metal is different from the molten metal injected into the contact limiting plate. Characterized by applying a refractory paint of gray degree, recognizing the surface of the basin by photographing the contact limiting plate with an optical surface recording camera, and controlling the surface level based on the recognition value Level control method for twin roll type continuous casting.